||[Jan. 7th, 2012|04:19 pm]
Spent four hours in the forge playing around with wootz. It's devilishly hard stuf to work with; fortunately, I'm more interested in it as a stock material to work into something useful. Still, according to what I've been reading, it's a good idea to "bake" the cakes at an orange heat for a few cycles, so I've did that today with the big chunk, and started trying to forge the smaller ones into something. Anything, really.|
I still maintain that this stuff just has too much carbon in it -- the forging temperature band is extremely narrow, probably around 100 degrees F, somewhere between a dull red and and bright red. Even then, I'm getting cracks and failures, though that could partially be due to the abuses I've inflicted on the steel during the learning process.
So, after getting frustrated watching the larger chunks turn into smaller chunks under the hammer, I decided to try an old viking trick. I cut out a rectangle of wrought iron sheet, and stacked some of the chunks of wootz onto it, fluxed, and tried to weld them together. It worked, at least well enough that I was able to add more chunks and start hammering the lot into a thinner bar. I started with a 6mm layer of wrought iron, and added to it about 20mm of the wootz, then started hammering that down. With the wrought iron backing, it's holding together, and it has welded up pretty solid. I worked the original 7.5cm x 10cm x 2.5cm billet to about 8cm x 15cm x 2cm without issue, mostly under the power hammer, before deciding I was running out of steam. I tossed the billet into the vermiculite tub to cool down slowly, next to the large wootz cake, as there is some speculation by fellow wootz-workers that slow cooling helps prevent unwanted cracking.
If I can draw this out into, say, a long thin ribbon, I'll probably roll it up on itself and forge weld it up, and then do the fold-and-weld thing until I'm happy with the carbon content and consistency.
Oh, before I pack the microscope up again, is there anything else you'd like photomicrographed?